166 Assessment of testicular echotexture in Nelore bulls: implications for puberty evaluation
B. Lima Chechin Catussi A , R. Germano de Rezende B , P. Nacib Jorge Neto A B , E. Gricio A , A. Echegaray C , L. Nataly Garcia-Oliveros A , E. C. Carvalho Celeghini A and P. Sampaio Baruselli AA
B
C
The objective of this study was to investigate the relationship between ultrasonographic echotexture parameters and puberty indicators in juvenile Nelore bulls. On a commercial farm, 104 Nelore (Bos indicus) bulls, aged 15.9 ± 0.21 months and weighing 482.2 ± 7.44 kg, were selected for analysis. Semen samples were collected via electroejaculation, and the echotexture of testicular parenchyma was assessed using B-mode ultrasonography (Exapad Mini, IMV Imaging) with a 7.5-MHz linear rectal probe. Each testicle was evaluated through two transverse cross sections (cranial to the central vein), and the videos were later analysed using Ecotext software (Humeco, Spain). Ecotext analyses yielded six echotexture parameters: Ecotext 1 (black pixels), Ecotext 2 (white pixels), and Ecotext 3 (grey pixels), in addition to three parameters related to hypoechogenic areas: Ecotext tubular density (density of tubules/cm2), Ecotext tubular diameter (mm), and Ecotext tubular area (percentage of hypoechogenic areas in the total area). Based on their puberty status, bulls were categorized as prepubertal (PRE; n = 49) if they did not produce sperm cells or produced fewer than 50 × 106 total cells, and pubertal (PUB; n = 55) if they produced more than 50 × 106 total sperm cells with more than 10% motility. The statistical significance was determined using a t-test, with a significance level set at P < 0.05. The analysis was performed using the GLIMMIX procedure of SAS 9.4. Compared with pubertal bulls, prepubertal bulls had a greater number of black pixels (Ecotext 1; 0.55 ± 0.19 vs 0.16 ± 0.05; P = 0.04). However, no significant differences were observed between groups in terms of white pixels (Ecotext 2; PRE = 979.3 ± 78.3 vs PUB = 970.9 ± 67.5; P = 0.93) or grey pixels (Ecotext 3; PRE = 122.9 ± 1.81 vs PUB = 124.7 ± 1.23; P = 0.40). Moreover, pubertal bulls exhibited greater tubular density (86.1 ± 1.75 vs 81.1 ± 2.23; P = 0.05) and larger tubular area (2.13 ± 0.11 vs 1.79 ± 0.10; P = 0.02) than prepubertal bulls. However, no significant differences in tubular diameter were observed between the two groups (PRE = 61.20 ± 1.15 vs PUB = 64.1 ± 1.07; P = 0.07). In conclusion, pubertal bulls revealed notable variations in the number of black pixels (Ecotext 1), tubular area, and tubular density when compared with prepubertal bulls. These findings suggest that Ecotext parameters have the potential to serve as reliable indicators for assessing precocity and puberty in Nelore bulls.
